The present invention, in some embodiments thereof, relates to amplification and, more particularly, but not exclusively, to a method and a system for parametric amplification.
Parametric amplification is a technique employed in oscillating systems wherein a parameter (e.g., inertia, a spring constant or affecting element's elastic stiffness) is modulated to produce amplification in the response of the system. Parametric amplifiers have generated sustained interest because their operational noise can be low. Parametric amplifiers typically combine a pump signal with an input signal to effect amplification or frequency conversion of the input signal.
Several implementations of this technique have been utilized in electronic systems, optical systems, and electromechanical systems. For example, U.S. Pat. No. 6,900,575 discloses a mechanical parametric device including two electrostatically coupled resonators, wherein a first resonator oscillates in response to an input signal, and a second resonator provides a feedback to amplify the oscillation of the first resonator.
Parametric amplifiers can be characterized as degenerate or non-degenerate. In a degenerate parametric amplifier, the frequency of the pump signal equals twice the input signal's frequency which also equals to the natural frequency of the amplifier. For any other relation between the pump signal, input signal and amplifier natural frequencies, the amplifier is characterized as a non-degenerate parametric amplifier. Degenerate parametric amplification provides a relatively high gain, but is not applicable when the input signal's frequency is not constant and when it does not coincide with the natural frequency. Non-degenerate parametric amplification is useful for input signals whose frequency is not pre-determined, but it has a relatively low gain.